Valve Bypass Instead of Replacement

A surgical procedure that bypasses a narrowed aortic valve, rather than replacing it, effectively restores blood flow from the heart to the rest of the body, says a new study. The researchers conclude that the procedure, called aortic valve bypass, is an important treatment option for high-risk elderly patients with a condition called aortic stenosis.

In aortic stenosis, calcium deposits narrow the aortic valve and impair the heart's ability to pump blood. During valve replacement, the surgeon opens the chest, stops the heart for about 90 minutes, opens the aorta, cuts out the old valve and sews in a new one. The bypass procedure, however, can be performed in a minimally invasive way without stopping the heart.

"Because of the possible risks associated with aortic valve replacement in the elderly, almost 60 percent of patients with symptoms related to aortic stenosis are not referred to surgery," says lead researcher James S. Gammie. These patients could benefit from the minimal-invasive procedure, Gammie argues.

In order to bypass the narrowed aortic valve, surgeons have refined a procedure from the 1970s. Most of the blood flow from the heart is diverted through a tube containing a standard replacement valve that is placed near the apex of the left ventricle to the aorta. The surgeons work through an incision between two ribs. During the first cases, a large incision was needed. However, the procedure was modified this year, so that a three-inch opening is enough.

Between 2003 and 2007, the surgeons treated 31 high-risk aortic stenosis patients with aortic valve bypass surgery. Many of the patients also had other conditions. The average age was 81, and nearly half had been refused conventional surgery. Early in the series, four of the 31 patients did not survive the procedure, yet there were no deaths among the most recent 16 consecutive patients.

The procedure was as effective as conventional aortic valve replacement surgery at relieving the obstruction of blood leaving the heart. Because the impaired aortic valve was left in place, some blood flow continued through that valve. But postsurgical blood flow measurements indicated that in most patients, approximately 70 percent of cardiac output flowed through the new bypass.